Displaying publications 101 - 120 of 371 in total

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  1. Reuniting the Biogeochemistry of Algae for a Low-Carbon Circular Bioeconomy
    Leong YK, Chew KW, Chen WH, Chang JS, Show PL
    Trends Plant Sci, 2021 07;26(7):729-740.
    PMID: 33461869 DOI: 10.1016/j.tplants.2020.12.010
    Given their advantages of high photosynthetic efficiency and non-competition with land-based crops, algae, that are carbon-hungry and sunlight-driven microbial factories, are a promising solution to resolve energy crisis, food security, and pollution problems. The ability to recycle nutrient and CO2 fixation from waste sources makes algae a valuable feedstock for biofuels, food and feeds, biochemicals, and biomaterials. Innovative technologies such as the bicarbonate-based integrated carbon capture and algae production system (BICCAPS), integrated algal bioenergy carbon capture and storage (BECCS), as well as ocean macroalgal afforestation (OMA), can be used to realize a low-carbon algal bioeconomy. We review how algae can be applied in the framework of integrated low-carbon circular bioeconomy models, focusing on sustainable biofuels, low-carbon feedstocks, carbon capture, and advances in algal biotechnology.
    Matched MeSH terms: Biofuels
  2. Salinity-induced microalgal-based mariculture wastewater treatment combined with biodiesel production
    Zhang C, Hasunuma T, Shiung Lam S, Kondo A, Ho SH
    Bioresour Technol, 2021 Nov;340:125638.
    PMID: 34358989 DOI: 10.1016/j.biortech.2021.125638
    Mariculture wastewater has drawn growing attention due to associated threats for coastal environment. However, most biological techniques exhibit unfavorable performance due to saline inhibition. Furthermore, only NaCl was used in most studies causing clumsy evaluation, undermining the potential of microalgal mariculture wastewater treatment. Herein, various concentrations of NaCl and sea salt are comprehensively examined and compared for their efficiencies of mariculture wastewater treatment and biodiesel conversion. The results indicate sea salt is a better trigger for treating wastewater (nearly 100% total nitrogen and total phosphorus removal) and producing high-quality biodiesel (330 mg/L•d). Structure equation model (SEM) further demonstrates the correlation of wastewater treatment performance and microalgal status is gradually weakened with increment of sea salt concentrations. Furthermore, metabolic analysis reveals enhanced photosynthesis might be the pivotal motivator for preferable outcomes under sea salt stimulation. This study provides new insights into microalgae-based approach integrating mariculture wastewater treatment and biodiesel production.
    Matched MeSH terms: Biofuels
  3. Oxidative torrefaction performance of microalga Nannochloropsis Oceanica towards an upgraded microalgal solid biofuel
    Zhang C, Ho SH, Chen WH, Wang R, Show PL, Ong HC
    J Biotechnol, 2021 Sep 10;338:81-90.
    PMID: 34298023 DOI: 10.1016/j.jbiotec.2021.07.009
    Microalgae are a promising feedstock for carbon-neutral biofuel production due to their superior cellular composition. Alternatively, oxidative torrefaction has been recognized as a potential thermochemical technique for microalgal solid biofuel upgrading. Herein, by using microalga N. oceanica as a feedstock, several characterizations are adopted for evaluating the potential of oxidative torrefaction towards microalgal solid biofuel production. The oxidatively torrefied microalgae can be upgraded as lignite. After in-depth analysis, significant change in the surface microstructure of oxidatively torrefied microalgae is largely changed (via wrinkle and fragmentation) The hydrophobicity, thermal decomposition, thermal stability, and aromatization of oxidatively torrefied microalgae can be largely enhanced as the oxidative torrefaction severity increase. With the increasing torrefaction temperature, the hydrophobicity of oxidative torrefied microalgae gradually improved. The decomposition of C-2/3/5, and -OCH3, the CO bonds of CH3CO-, and the aromatization occurs via oxidative torrefaction according to the NMR analysis. For XPS analysis, torrefaction operation significantly decreases the carbide carbon and enhances the graphitization. As a result, the thermal stability of oxidatively torrefied microalgae is improved. Conclusively, the information obtained in this study can provide insights into the evaluation of oxidative torrefaction performance and fuel properties of microalgal solid biofuel, which may help accelerate the advancement of oxidative torrefaction industrialization.
    Matched MeSH terms: Biofuels
  4. Fulltext Latest development in microalgae-biofuel production with nano-additives
    Hossain N, Mahlia TMI, Saidur R
    Biotechnol Biofuels, 2019;12:125.
    PMID: 31139255 DOI: 10.1186/s13068-019-1465-0
    Background: Microalgae have been experimented as a potential feedstock for biofuel generation in current era owing to its' rich energy content, inflated growth rate, inexpensive culture approaches, the notable capacity of CO2 fixation, and O2 addition to the environment. Currently, research is ongoing towards the advancement of microalgal-biofuel technologies. The nano-additive application has been appeared as a prominent innovation to meet this phenomenon.

    Main text: The main objective of this study was to delineate the synergistic impact of microalgal biofuel integrated with nano-additive applications. Numerous nano-additives such as nano-fibres, nano-particles, nano-tubes, nano-sheets, nano-droplets, and other nano-structures' applications have been reviewed in this study to facilitate microalgae growth to biofuel utilization. The present paper was intended to comprehensively review the nano-particles preparing techniques for microalgae cultivation and harvesting, biofuel extraction, and application of microalgae-biofuel nano-particles blends. Prospects of solid nano-additives and nano-fluid applications in the future on microalgae production, microalgae biomass conversion to biofuels as well as enhancement of biofuel combustion for revolutionary advancement in biofuel technology have been demonstrated elaborately by this review. This study also highlighted the potential biofuels from microalgae, numerous technologies, and conversion processes. Along with that, the study recounted suitability of potential microalgae candidates with an integrated design generating value-added co-products besides biofuel production.

    Conclusions: Nano-additive applications at different stages from microalgae culture to end-product utilization presented strong possibility in mercantile approach as well as positive impact on the environment along with valuable co-products generation into the near future.

    Matched MeSH terms: Biofuels
  5. Potential utilization of bioproducts from microalgae for the quality enhancement of natural products
    Tang DYY, Khoo KS, Chew KW, Tao Y, Ho SH, Show PL
    Bioresour Technol, 2020 May;304:122997.
    PMID: 32094007 DOI: 10.1016/j.biortech.2020.122997
    Microalgae are autotroph organisms that utilise light energy to synthesize various high-value bioactive compounds such as polysaccharides, proteins and lipids. Due to its fast growth rate and capability to survive in harsh environment, microalgae nowadays are applied in various industrial areas. The process of obtaining microalgae-based biomolecules starts with the selection of suitable microalgae strain, cultivation, followed by downstream processing of the biomass (i.e., pre-treatment, harvesting, extraction and purification). The end products of the processes are biofuels and other valuable bioproducts. Nevertheless, low production yield and high-cost downstream processes are the emerging bottlenecks which need to be addressed in the upscaling of extracted compounds from microalgae biomass. To conclude, tremendous efforts are required to overcome these challenges to revolutionize microalgae into a novel and green factory of different bioactive compounds for industrial necessities to satisfy and fulfil global demands.
    Matched MeSH terms: Biofuels
  6. Recent advances in downstream processing of microalgae lipid recovery for biofuel production
    Khoo KS, Chew KW, Yew GY, Leong WH, Chai YH, Show PL, et al.
    Bioresour Technol, 2020 May;304:122996.
    PMID: 32115347 DOI: 10.1016/j.biortech.2020.122996
    The world energy system faces two major challenges: the requirement for more energy and less carbon. It is important to address biofuels production as an alternative to the usage of fossil fuel by utilizing microalgae as the potential feedstock. Yet, the commercialization of microalgae remains contentious caused by factors relating to the life cycle assessment and feasibility of microalgae-based biofuels. This present review starts with an introduction to the benefits of microalgae, followed by intensive elaboration on microalgae cultivation parameters. Subsequently, the fundamental principle along with the advantages and disadvantages of various pretreatment techniques of microalgae were reviewed. In addition, the conventional and recent advances in lipid extraction techniques from microalgae were comprehensively evaluated. Comparative analysis regard to the gaps from previous studies was discussed point-by-point in each section. The effort presented in this review will provide an insight for future researches dealing with microalgae-biofuel production on downstream processing.
    Matched MeSH terms: Biofuels
  7. Microwave assisted acid hydrolysis for bioethanol fuel production from sago pith waste
    Thangavelu SK, Rajkumar T, Pandi DK, Ahmed AS, Ani FN
    Waste Manag, 2019 Mar 01;86:80-86.
    PMID: 30902242 DOI: 10.1016/j.wasman.2019.01.035
    Microwave assisted acid hydrolysis (H2SO4 and HCl with >0.5 mol/L) to produce bioethanol from sago pith waste (SPW) was studied. The energy consumption for microwave hydrolysis at different energy inputs and acid concentration were calculated. The overall energy consumption for bioethanol fuel production from SPW was assessed. A maximum of 88% glucose yield and 80% ethanol yield (3.1 g ethanol per 10 g SPW) were obtained using 1.0 mol/L H2SO4. Microwave hydrolysis using 1.0 mol/L H2SO4 consumed the minimum energy of 8.1 kJ to produce 1 g glucose from SPW when energy input was fixed at 54 kJ (900 W for 1 min). In general, 1 g glucose can produce 16 kJ. The overall energy consumption for fuel grade bioethanol production from SPW was 31.77 kJ per g ethanol, which was slightly higher than the lower heating values of ethanol (26.74 kJ/g ethanol).
    Matched MeSH terms: Biofuels
  8. Valorization of exo-microbial fermented coconut endosperm waste by black soldier fly larvae for simultaneous biodiesel and protein productions
    Wong CY, Lim JW, Chong FK, Lam MK, Uemura Y, Tan WN, et al.
    Environ Res, 2020 06;185:109458.
    PMID: 32247911 DOI: 10.1016/j.envres.2020.109458
    The conventional practice in enhancing the larvae growths is by co-digesting the low-cost organic wastes with palatable feeds for black soldier fly larvae (BSFL). In circumventing the co-digestion practice, this study focused the employment of exo-microbes in a form of bacterial consortium powder to modify coconut endosperm waste (CEW) via fermentation process in enhancing the palatability of BSFL to accumulate more larval lipid and protein. Accordingly, the optimum fermentation condition was attained by inoculating 0.5 wt% of bacterial consortium powder into CEW for 14-21 days. The peaks of BSFL biomass gained and growth rate were initially attained whilst feeding the BSFL with optimum fermented CEW. These were primarily attributed by the lowest energy loss via metabolic cost, i.e., as high as 22% of ingested optimum fermented CEW was effectively bioconverted into BSFL biomass. The harvested BSFL biomass was then found containing about 40 wt% of lipid, yielding 98% of fatty acid methyl esters of biodiesel upon transesterification. Subsequently, the protein content was also analyzed to be 0.32 mg, measured from 20 harvested BSFL with a corrected-chitin of approximately 8%. Moreover, the waste reduction index which represents the BSFL valorization potentiality was recorded at 0.31 g/day 20 BSFL. The benefit of fermenting CEW was lastly unveiled, accentuating the presence of surplus acid-producing bacteria. Thus, it was propounded the carbohydrates in CEW were rapidly hydrolysed during fermentation, releasing substantial organic acids and other nutrients to incite the BSFL assimilation into lipid for biodiesel and protein productions simultaneously.
    Matched MeSH terms: Biofuels
  9. Effect of oxide catalysts on the properties of bio-oil from in-situ catalytic pyrolysis of palm empty fruit bunch fiber
    Chong YY, Thangalazhy-Gopakumar S, Ng HK, Lee LY, Gan S
    J Environ Manage, 2019 Oct 01;247:38-45.
    PMID: 31229784 DOI: 10.1016/j.jenvman.2019.06.049
    Fast pyrolysis is a potential technology for converting lignocellulosic biomass into bio-oil. Nevertheless, the high amounts of acid, oxygenated compounds, and water content diminish the energy density of the bio-oil and cause it to be unsuitable for direct usage. Catalytic fast pyrolysis (CFP) is able to improve bio-oil properties so that downstream upgrading processes can be economically feasible. Here, calcium oxide (CaO), magnesium oxide (MgO), and zinc oxide (ZnO) were employed due to their potential in enhancing bio-oil properties. The results showed that overall, all three catalysts positively impacted the empty fruit bunch fibre-derived bio-oil properties. Among the catalysts, CaO showed the most favorable effects in terms of reducing the acidity of the bio-oil and anhydrosugar. Thermal stability of bio-oils produced in the presence of CaO was studied as well.
    Matched MeSH terms: Biofuels
  10. Recent advances on the sustainable approaches for conversion and reutilization of food wastes to valuable bioproducts
    Ng HS, Kee PE, Yim HS, Chen PT, Wei YH, Chi-Wei Lan J
    Bioresour Technol, 2020 Apr;302:122889.
    PMID: 32033841 DOI: 10.1016/j.biortech.2020.122889
    The increasing amounts of food wastage and accumulation generated per annum due to the growing human population worldwide often associated with environmental pollution issues and scarcity of natural resources. In view of this, science community has worked towards in finding sustainable approaches to replace the common practices for food waste management. The agricultural and food processing wastes rich in nutrients are often the attractive substrates for the bioconversion for valuable bioproducts such as industrial enzymes, biofuel and bioactive compounds. The sustainable approaches on the re-utilization of food wastes as the industrial substrates for production of valuable bioproducts has meet the goals of circular bioeconomy, results in the diversify applications and increasing market demands for the bioproducts. This review discusses the current practice and recent advances on reutilization of food waste for bioconversion of valuable bioproducts from agricultural and food processing wastes.
    Matched MeSH terms: Biofuels
  11. Investigating the effects of eleven key physicochemical factors on growth and lipid accumulation of Chlorella sp. as a feedstock for biodiesel production
    Parichehreh R, Gheshlaghi R, Mahdavi MA, Kamyab H
    J Biotechnol, 2021 Nov 10;340:64-74.
    PMID: 34454961 DOI: 10.1016/j.jbiotec.2021.08.010
    Biodiesel, as a renewable and eco-friendly energy source that can be produced through algae oil esterification, has recently received much attention. Maximization of algal biomass and lipid content is crucial for commercial biodiesel production. In this study, Chlorella sp. PG96, a microalgal strain isolated from urban wastewater, was identified considering its morphological and molecular characteristics. Fractional factorial design (211-7) was employed to screen medium and environmental factors for achieving high lipid productivity. The effects of eleven factors including light intensity, light spectrum, aeration rate, temperature, salinity, NaHCO3, CO2, NaNO3, NH4Cl, MgSO4.7H2O, and K2HPO4 and their interactions on growth characteristics of Chlorella sp. PG96 (biomass and lipid production) were statistically assessed. Based on the experimental results, lipid productivity was at its maximum (54.19 ± 8.40 mglipid L-1 day-1) under a combination of high levels of all factors. The analysis also showed that physical parameters of light intensity and temperature were more effective on algal growth compared to nutritional parameters. Furthermore, nitrogen source of ammonium and carbon source of bicarbonate played more significant roles in biomass and lipid production, compared with nitrate and CO2, respectively. Although the effect of sulfur limitation on cellular growth was similar to phosphorus deficiency, S-limitation had a greater impact on lipid accumulation. The interaction between NaHCO3 and NH4Cl was the most prominent interaction affecting all responses. It is concluded that Chlorella sp. PG96 at a high level of light intensity and temperature (22500 Lux and 32 °C, respectively) can be a prospective candidate for biodiesel production.
    Matched MeSH terms: Biofuels
  12. Algae as potential feedstock for various bioenergy production
    Chia SR, Nomanbhay SBHM, Chew KW, Munawaroh HSH, Shamsuddin AH, Show PL
    Chemosphere, 2022 Jan;287(Pt 1):131944.
    PMID: 34438210 DOI: 10.1016/j.chemosphere.2021.131944
    Depletion of non-renewable feedstock and severe wastewater pollution due to human activities have created negative impact to living organisms. The potential solution is to implement wastewater treatment and bioelectricity production through algae-based microbial fuel cell. The algae biomass produced from microbial fuel cell could be further processed to generate biofuels through their unique compositions. The consumption of nutrients in wastewater through algae cultivation and biomass produced to be utilized for energy supply have showed the potential of algae to solve the issues faced nowadays. This review introduces the background of algae and mitigation of wastewater using algae as well as the bioenergy status in Malaysia. The mechanisms of nutrient assimilation such as nitrogen, phosphorus, carbon, and heavy metals are included, followed by the application of algae in microbial fuel cell's chambers. Lastly, the status of algae for bioenergy production are covered.
    Matched MeSH terms: Biofuels
  13. State-of-the-art of the pyrolysis and co-pyrolysis of food waste: Progress and challenges
    Su G, Ong HC, Fattah IMR, Ok YS, Jang JH, Wang CT
    Sci Total Environ, 2022 Feb 25;809:151170.
    PMID: 34699825 DOI: 10.1016/j.scitotenv.2021.151170
    The continuous growth of population and the steady improvement of people's living standards have accelerated the generation of massive food waste. Untreated food waste has great potential to harm the environment and human health due to bad odor release, bacterial leaching, and virus transmission. However, the application of traditional disposal techniques like composting, landfilling, animal feeding, and anaerobic digestion are difficult to ease the environmental burdens because of problems such as large land occupation, virus transmission, hazardous gas emissions, and poor efficiency. Pyrolysis is a practical and promising route to reduce the environmental burden by converting food waste into bioenergy. This paper aims to analyze the characteristics of food waste, introduce the production of biofuels from conventional and advanced pyrolysis of food waste, and provide a basis for scientific disposal and sustainable management of food waste. The review shows that co-pyrolysis and catalytic pyrolysis significantly impact the pyrolysis process and product characteristics. The addition of tire waste promotes the synthesis of hydrocarbons and inhibits the formation of oxygenated compounds efficiently. The application of calcium oxide (CaO) exhibits good performance in the increment of bio-oil yield and hydrocarbon content. Based on this literature review, pyrolysis can be considered as the optimal technique for dealing with food waste and producing valuable products.
    Matched MeSH terms: Biofuels
  14. Design of biorefineries towards carbon neutrality: A critical review
    Culaba AB, Mayol AP, San Juan JLG, Ubando AT, Bandala AA, Concepcion Ii RS, et al.
    Bioresour Technol, 2023 Feb;369:128256.
    PMID: 36343780 DOI: 10.1016/j.biortech.2022.128256
    The increase in worldwide demand for energy is driven by the rapid increase in population and exponential economic development. This resulted in the fast depletion of fossil fuel supplies and unprecedented levels of greenhouse gas in the atmosphere. To valorize biomass into different bioproducts, one of the popular and carbon-neutral alternatives is biorefineries. This system is an appropriate technology in the circular economy model. Various research highlighted the role of biorefineries as a centerpiece in the carbon-neutral ecosystem of technologies of the circular economy model. To fully realize this, various improvements and challenges need to be addressed. This paper presents a critical and timely review of the challenges and future direction of biorefineries as an alternative carbon-neutral energy source.
    Matched MeSH terms: Biofuels
  15. Reduction in environmental CO2 by utilization of optimized energy scheme for power and fresh water generations based on different uses of biomass energy
    Hai T, Ali MA, Alizadeh A, Almojil SF, Almohana AI, Alali AF
    Chemosphere, 2023 Apr;319:137847.
    PMID: 36657576 DOI: 10.1016/j.chemosphere.2023.137847
    Renewable energy sources are undoubtedly necessary, considering global electricity demand is expected to rise dramatically in the coming years. This research looks at a unique multi-generation plant from the perspectives of exergy, energy, and economics; also, an environmental evaluation is performed to estimate the systems' CO2 emissions. The unit is made up of a biomass digester and gasifier, a Multi effect Desalination unit, and a supercritical CO2 (SCO2) cycle. In this study, two methods for using biomass are considered: the first is using synthesis gas generated by the gasifier, and the second is utilizing a digester to generate biogas. A comprehensive parametric study is performed on the designed energy unit to assess the influence of compressor pressure ratio, Gas turbine inlet temperature, supercritical CO2 cycle pressure ratio, and the number of effects of multi-effect distillation on the system performance. Furthermore, the exergy study revealed that the exergy destruction in the digestion unit was 11,337 kW, which was greater than the exergy destruction in the gasification unit, which was 9629. Finally, when compared to the gasifier, the amount of exergy efficiency, net output power, and freshwater production in the digester was greater.
    Matched MeSH terms: Biofuels
  16. A comprehensive review on nanocatalysts and nanobiocatalysts for biodiesel production in Indonesia, Malaysia, Brazil and USA
    Mahdi HI, Ramlee NN, da Silva Duarte JL, Cheng YS, Selvasembian R, Amir F, et al.
    Chemosphere, 2023 Apr;319:138003.
    PMID: 36731678 DOI: 10.1016/j.chemosphere.2023.138003
    Biodiesel is an alternative to fossil-derived diesel with similar properties and several environmental benefits. Biodiesel production using conventional catalysts such as homogeneous, heterogeneous, or enzymatic catalysts faces a problem regarding catalysts deactivation after repeated reaction cycles. Heterogeneous nanocatalysts and nanobiocatalysts (enzymes) have shown better advantages due to higher activity, recyclability, larger surface area, and improved active sites. Despite a large number of studies on this subject, there are still challenges regarding its stability, recyclability, and scale-up processes for biodiesel production. Therefore, the purpose of this study is to review current modifications and role of nanocatalysts and nanobiocatalysts and also to observe effect of various parameters on biodiesel production. Nanocatalysts and nanobiocatalysts demonstrate long-term stability due to strong Brønsted-Lewis acidity, larger active spots and better accessibility leading to enhancethe biodiesel production. Incorporation of metal supporting positively contributes to shorten the reaction time and enhance the longer reusability. Furthermore, proper operating parameters play a vital role to optimize the biodiesel productivity in the commercial scale process due to higher conversion, yield and selectivity with the lower process cost. This article also analyses the relationship between different types of feedstocks towards the quality and quantity of biodiesel production. Crude palm oil is convinced as the most prospective and promising feedstock due to massive production, low cost, and easily available. It also evaluates key factors and technologies for biodiesel production in Indonesia, Malaysia, Brazil, and the USA as the biggest biodiesel production supply.
    Matched MeSH terms: Biofuels
  17. A foam column system harvesting freshwater algae for biodiesel production: An experiment and process model evaluations
    Al-Humairi ST, Lee JGM, Harvey AP, Salman AD, Juzsakova T, Van B, et al.
    Sci Total Environ, 2023 Mar 01;862:160702.
    PMID: 36481155 DOI: 10.1016/j.scitotenv.2022.160702
    The purpose of this study was to examine the application of the mathematical model of drift flux to the experimental results of the effect of cationic trimethyl-ammonium bromide (CTAB)-aided continuous foam flotation harvesting on the lipid content in Chlorella vulgaris microalgae. An experiment was conducted to determine the effect of the operating conditions on the enrichment factor (EF) and percentage recovery efficiency (%RE), where the flow rates at the inlet and bottom outlet remained constant. Data for the binary system (without algae) and ternary system (with algae) in an equal-area foam column show that the EF decreases linearly with increasing initial CTAB concentrations ranging from 30 to 75 mg/L for three levels of the studied air volumetric flow rate range (1-3) L/min. The percentage harvesting efficiency increased with increasing initial CTAB concentration and air volumetric flow rate to 96 % in the binary systems and 94 % in the ternary systems. However, in the foam column with the riser used in the three systems, a lower volume of liquid foam in the upward outlet stream resulted in a lower RE% than that of the column without the riser. The objective function of EF for the system with algae increased when the initial CTAB concentration was increased from 30 to 45 mg/L in the foam column with a riser for all air flow rates, and after 45 mg/L, a sudden drop in the microalgae EF was observed. In the comparison between the foam column with and without the riser for the system with algae, the optimum EF was 145 for the design of the column with the riser and 139 for the column without the riser.
    Matched MeSH terms: Biofuels
  18. Microalgae-based biotechnological sequestration of carbon dioxide for net zero emissions
    Ma Z, Cheah WY, Ng IS, Chang JS, Zhao M, Show PL
    Trends Biotechnol, 2022 Dec;40(12):1439-1453.
    PMID: 36216714 DOI: 10.1016/j.tibtech.2022.09.002
    Excessive carbon dioxide (CO2) emissions into the atmosphere have become a dire threat to the human race and environmental sustainability. The ultimate goal of net zero emissions requires combined efforts on CO2 sequestration (natural sinks, biomass fixation, engineered approaches) and reduction in CO2 emissions while delivering economic growth (CO2 valorization for a circular carbon bioeconomy, CCE). We discuss microalgae-based CO2 biosequestration, including flue gas cultivation, biotechnological approaches for enhanced CO2 biosequestration, technological innovations for microalgal cultivation, and CO2 valorization/biofuel productions. We highlight challenges to current practices and future perspectives with the goal of contributing to environmental sustainability, net zero emissions, and the CCE.
    Matched MeSH terms: Biofuels
  19. Self-flocculation of enriched mixed microalgae culture in a sequencing batch reactor
    Gobi S, Gobi K, Lee KT, Vadivelu V
    Environ Sci Pollut Res Int, 2021 Jun;28(21):26595-26605.
    PMID: 33484460 DOI: 10.1007/s11356-021-12615-4
    Microalgae-based biodiesel has gained widespread interest as an alternative energy source. Low-cost microalgae harvesting technologies are important for economically feasible biodiesel production. This study investigated, for the first time, the impact of adaptation period and height to diameter (H/D) ratio of a reactor on the growth and self-flocculation of microalgae, without the addition of bacteria. Six reactors were grouped into three sets of experiments, and each reactor was operated for 30 days at similar operating conditions (volume exchange ratio = 25% and settling time = 30 min). In set 1, two 8-L reactors, H5a (H/D ratio: 5) and H8a (H/D ratio: 8), were operated under batch operation. In set 2, reactors H5b and H8b were operated as sequential batch reactors (SBRs) without an adaptation period. In set 3, the reactors H5c and H8c were operated as SBRs with an adaptation period. The findings showed a threefold improvement in biomass productivity for the higher H/D ratio (H8c) and a reduction in biomass loss for microalgae. The H8c reactor exhibited 95% settling efficiency within 5 days, in comparison to 30 days for the H5c reactor. This study demonstrated that a higher H/D ratio and the introduction of an adaptation period in SBR operation positively influences growth and self-flocculation of enriched mixed microalgae culture.
    Matched MeSH terms: Biofuels
  20. Improving the decolorization of glycerol by adsorption using activated carbon derived from oil palm biomass
    Ahmad Farid MA, Hassan MA, Roslan AM, Ariffin H, Norrrahim MNF, Othman MR, et al.
    Environ Sci Pollut Res Int, 2021 Jun;28(22):27976-27987.
    PMID: 33527241 DOI: 10.1007/s11356-021-12585-7
    This study provides insight into the decolorization strategy for crude glycerol obtained from biodiesel production using waste cooking oil as raw material. A sequential procedure that includes physico-chemical treatment and adsorption using activated carbon from oil palm biomass was investigated. The results evidenced decolorization and enrichment of glycerol go hand in hand during the treatment, achieving >89% color removal and > 98% increase in glycerol content, turning the glycerol into a clear (colorless) solution. This is attributed to the complete removal of methanol, free fatty acids, and triglycerides, as well as 85% removal of water, and 93% removal of potassium. Properties of the resultant glycerol met the quality standard of BS 2621:1979. The economic aspects of the proposed methods are examined to fully construct a predesign budgetary estimation according to chemical engineering principles. The starting capital is proportionate to the number of physical assets to acquire where both entail a considerable cost at USD 13,200. Having the benefit of sizeable scale production, it reasonably reduces the operating cost per unit product. As productivity sets at 33 m3 per annum, the annual operating costs amount to USD 79,902 in glycerol decolorization. This is translatable to USD 5.38 per liter glycerol, which is ~69% lower compared to using commercial activated carbon.
    Matched MeSH terms: Biofuels
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